Zmanco Posted July 9, 2012 Share Posted July 9, 2012 I've had a recurring problem with the nuts that hold the turbo to the exhaust manifold coming lose on track days. This last attempt I used the deformed thread copper nuts but that just slowed the process down. Due to interfearance issues with the T3/T4 turbo I have to pull the head and remove the manifold to get to the bolts so this is the last time I want to do this. I recall that when I removed the factory T3 turbo that the bolts were secured via a piece of soft metal that was bent up around them. There were 2 of these pieces with each one spanning across 2 studs. I've found it in the FSM but there's no part number. Does anyone know how/where to source these, or perhaps where to get a small sheet of the metal so I can make my own? Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted July 10, 2012 Share Posted July 10, 2012 Im bummed I missed the last track day at HPR! I had to work! Daniel, I can look around my storage totes and see if I have any spares of those brackets. Just outta curiosity, have you tried using loc-tite? You can also use a combo of things to secure this... and finally Lots of good, affordable options =) Quote Link to comment Share on other sites More sharing options...
LanceVance Posted July 10, 2012 Share Posted July 10, 2012 (edited) Listed for Z31s, but THIS (Part No. 14495-Z31002) should be what your looking for. You might also consider safety wire. Its called a locking tab bracket or plate lock, and seeing as the Z31 has the same T3 flange, I doubt you'll have any problem with these. Post your results! I might just pick some up when my turbo build starts coming together. Edit: Added part number. Edited July 10, 2012 by LanceVance Quote Link to comment Share on other sites More sharing options...
letitsnow Posted July 10, 2012 Share Posted July 10, 2012 I haven't had an issue, I used steel nuts(std, not locking in any way). I'm afraid of them breaking the studs now due to corrosion, they've been on for 3 years and I've had the manifold and turbo glowing more times than I can count, but no track days. Safety wire won't work on nuts, and it's also not designed to hold torque, that's up to the fastener and torque specs. Your options are fairly limited to deformed thread nuts. Maybe get some SS ones. Quote Link to comment Share on other sites More sharing options...
LanceVance Posted July 10, 2012 Share Posted July 10, 2012 He could use safety wire, although it would require he convert to bolts or drill the stud and use castle nuts. Safety wire may not hold torque, but it is designed to maintain it! Quote Link to comment Share on other sites More sharing options...
Zmanco Posted July 10, 2012 Author Share Posted July 10, 2012 (edited) Im bummed I missed the last track day at HPR! I had to work! Daniel, I can look around my storage totes and see if I have any spares of those brackets. Just outta curiosity, have you tried using loc-tite? You can also use a combo of things to secure this... and finally Lots of good, affordable options =) Ryan, thanks for the suggestions. I had started looking at Loctite but didn't see any products that could live in that heat range. Same issue for any washers that are spring steel - the heat takes out the "spring". Sorry you couldn't come out to the track - it was a fantastic day as the threat of rain kept the temps somewhat lower (mid 80's) and the rain stay away until 10 minutes after we left the track - total luck! When will you have your car back on the road? And at the risk of hijacking my own thread, here's . Edited July 10, 2012 by Zmanco Quote Link to comment Share on other sites More sharing options...
Zmanco Posted July 10, 2012 Author Share Posted July 10, 2012 Listed for Z31s, but THIS should be what your looking for. You might also consider safety wire. Its called a locking tab bracket or plate lock, and seeing as the Z31 has the same T3 flange, I doubt you'll have any problem with these. Post your results! I might just pick some up when my turbo build starts coming together. Thanks, that's exactly what I need. I had searched using the 280zx turbo with no luck and didn't realize the early 300zx used the same turbo. Sweet! I noticed that the corresponding nut is listed at $6.27 each. Are these deformed threads, or something else unique? Otherwise what's so special that they want $25 for the set of 4? Quote Link to comment Share on other sites More sharing options...
Zmanco Posted July 10, 2012 Author Share Posted July 10, 2012 I haven't had an issue, I used steel nuts(std, not locking in any way). I'm afraid of them breaking the studs now due to corrosion, they've been on for 3 years and I've had the manifold and turbo glowing more times than I can count, but no track days. I started with steel nuts but they backed off after the first track day. I thought the issue was due to the exhaust so added a flex pipe right after where a NA header flange would be. I also later added a bracket near there to the tranny. Both seem to have made things better, but obviously I haven't cured the issue. I obviously couldn't see under the hood while on the track, but after about 15 minutes into a 20 minute session had to back off as the water temps were approaching 240 and oil was over 250. But I was being chased by an LS3 Miata and another with Flying Miata turbo (300 whp) and didn't want to slow. Turned out that as soon as I let up for them to pass, both were in the same overheating situation and stayed behind me. We had a good laugh afterward. Quote Link to comment Share on other sites More sharing options...
neotech84 Posted July 10, 2012 Share Posted July 10, 2012 (edited) Yes safety wire is for holding BOLTS in place AFTER they are torqued. Nuts would limit you to a self locking type, a lock washer stack up or a castleated nut. Lock-tight would be an extra measure to either option. Edited July 10, 2012 by neotech84 Quote Link to comment Share on other sites More sharing options...
Zmanco Posted July 11, 2012 Author Share Posted July 11, 2012 I ordered the Plate-Lock and Nuts from Courtesy Nissan today - I'm assuming the nuts are deformed thread to justify their price of $6 each. A few of you mentioned Loc-Tite. I had looked some time ago but didn't see anything rated for exhaust temps. Is there a version for that application? Quote Link to comment Share on other sites More sharing options...
rossman Posted July 11, 2012 Share Posted July 11, 2012 (edited) There is no Loctite rated for exhaust manifold temperatures. BTW the lockwire shown in the propeller hub picture is installed incorrectly. Lockwire needs to wrap around and pull tangentially on the bolt head in a manner which tends to tighten the bolt. Edited July 11, 2012 by rossman Quote Link to comment Share on other sites More sharing options...
LanceVance Posted July 11, 2012 Share Posted July 11, 2012 HERE is a good guide on safety wire technique. It's in reference to ultralight aircraft, so it should be more than appropriate for our on the ground applications! Quote Link to comment Share on other sites More sharing options...
djz Posted July 12, 2012 Share Posted July 12, 2012 I used Nord Lock washers on my car. I don't really see drilling the studs and nuts to lock wire them as being very practical. Quote Link to comment Share on other sites More sharing options...
rossman Posted July 12, 2012 Share Posted July 12, 2012 Those depend on the serrations digging into the flange surface. I imagine they don't grip reliably on hard steel. But, it's probably worth a shot since exhaust flange bolts are not safety critical. With lockwire and tabbed washers, you know they will work if installed correctly. Quote Link to comment Share on other sites More sharing options...
Tony D Posted July 12, 2012 Share Posted July 12, 2012 Ditto the loctite comment, it releases it's hold at 400F... As for not using lockwire on nuts...uh... "why not"? There are plenty of military assemblies with safety-wired nuts, though Grade-C locknuts make for quicker assembly. If your nuts are coming loose, you are not properly torquing them to proper tension beforehand. Got to the "Bolt Science" website, and run their example video of the "Junkers Test" to see why tightening a bolt properly is the ONLY mechanical method to prevent loosening, and why split lockwashers and most other lockwashers are a waste of time when it comes to high vibration assemblies. Quote Link to comment Share on other sites More sharing options...
LanceVance Posted July 26, 2012 Share Posted July 26, 2012 I ordered the Plate-Lock and Nuts from Courtesy Nissan today - I'm assuming the nuts are deformed thread to justify their price of $6 each. Any updates? Quote Link to comment Share on other sites More sharing options...
Zmanco Posted August 1, 2012 Author Share Posted August 1, 2012 Nuts are deformed thread. Here's a picture of the platelock along with part number. Unfortunately I found damage to the compressor wheel when I took things apart so that's slowing me down in getting it all reassembled. Quote Link to comment Share on other sites More sharing options...
Zmanco Posted August 20, 2012 Author Share Posted August 20, 2012 Got it all back together this weekend and all is well with the universe again. But for those who may be doing this for the first time, here's a summary of what I learned about attaching the T3/TO4E turbo to the stock manifold: Make sure you use the Plate-lock 14495-V5300 to secure the nuts on the exhaust manifold studs. Without those, expect the nuts to back off after a few thousand miles. This shows NLA for the 280ZX turbo, but still shows up for the Z31 300ZX with T3 turbo. The deformed thread nuts from Nissan must be some other thread size as it destroyed the threads on the first stud I tried. Save your money and avoid them. Instead, use steel conical-top nuts from McMaster 93795A240. Much cheaper too. For studs, I ordered 2 types from McMaster 93275A039 (M10 x 1.5 50mm) and 91059A561 M10 x 1.5 52mm). The 561 are described as self locking, but I didn't notice any difference. However, they have shorter threads on one end which is useful when using the T3/TO4E which requires a spacer. With the 039 it would be easy to put them in too far and not have enough threads left for the nuts. Lastly, I found that assembling the turbo housing to the manifold BEFORE installing the turbo wheels made it easy to get the wrench properly on the nuts. With the turbo fully assembled, it's not easy. Lastly, before you pull the turbo apart, make sure you scribe a line for the alignment of the center section. I used a sharpee and I think the Kroil removed the mark. Having to line it up and tighten the center section bolts on the car isn't that much fun, but it is a good excuse to get a set of stubby metric wrenches. Quote Link to comment Share on other sites More sharing options...
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